Essex class aircraft carrier

"Essex" was a class of aircraft carriers of the United States Navy, which constituted the 20th century's most numerous class of heavy warships, with 24 ships built. These included members of the "long-hull" "Ticonderoga" variant/subclass, which some consider a separate class. Thirty-two were originally ordered, however six were cancelled before construction, and two were cancelled after construction had begun. The "Essex"-class carriers, along with the three "Midway"-class, were the backbone of the Navy's combat strength from the later years of World War II, until the supercarriers began to come into the fleet in numbers during the 1960s and 1970s.

Overview

The preceding "Yorktown"s formed the basis from which the "Essex" class was developed. Designed to carry a larger air group, and unencumbered by pre-war naval treaty limits, USS|Essex|CV-9|6 (CV-9) was over sixty feet longer, nearly ten feet wider in beam, and more than a third heavier. A longer, wider flight deck and a deck-edge elevator facilitated more efficient aviation operations, enhancing the ship's offensive and defensive air power. Machinery arrangement and armor protection was greatly improved from previous designs. These features, plus the provision of more anti-aircraft guns, gave the ships much enhanced survivability. In fact, none of the "Essex"-class carriers were lost and two, USS|Franklin|CV-13|3 and USS|Bunker Hill|CV-17|3, came home under their own power even after receiving heavy damage.

U.S. carriers had the same amount of deck armor as their British counterparts. While debates raged, and continue to this day, regarding the effect of strength deck location (flight deck level on British ships vs. hangar deck level on American ships), British designers' comments tended to disparage the use of deck armor, but some historians, such as D.K. Brown in "Nelson to Vanguard", see the American arrangement to have been superior, until the larger size of the first supercarriers necessitated a deeper hull, and thus moving the strength deck to the flight deck.

Development

After the abrogation of disarmament treaties by Japan in 1936, the U.S. took a realistic look at its naval strength. With the Naval Expansion Act of Congress passed on May 17, 1938, an increase of 40,000 tons in aircraft carriers was authorized. This permitted the building of USS|Hornet|CV-8|6 (CV-8) and USS|Essex|CV-9|6 (CV-9), which became the lead ship of her class.

CV-9 was to be the prototype of the 27,000-ton (standard displacement) aircraft carrier, considerably larger than USS|Enterprise|CV-6|3, yet smaller than USS|Saratoga|CV-3|3 (a battlecruiser converted to a carrier). These were to become known as "Essex"-class carriers, although this classification was later dropped in the 1950s. On September 9, 1940, eight more of these carriers were ordered: USS|Hornet|CV-12|3, USS|Franklin|CV-13|3, USS|Ticonderoga|CV-14|2 (CV -14), USS|Randolph|CV-15|3, USS|Lexington|CV-16|3, USS|Bunker Hill|CV-17|3, USS|Wasp|CV-18|3, and USS|Hancock|CV-19|3. The last two of the 13 originally programmed CV-9 class aircraft carriers, USS|Bennington|CV-20|3 and USS|Boxer|CV-21|3, were ordered on December 15, 1941.

It should be noted "Lexington", "Wasp", "Hornet", and "Yorktown" were renamed during construction, in keeping with the Navy's intent to carry on the traditions of their fighting predecessors, sunk in combat in 1942. It should also be noted that of the original 13 ordered "Essex"-class ships, several ("Ticonderoga" {CV-14}, "Randolph" {CV-15}, "Hancock" {CV-19}, and "Boxer" {CV-21}) were modified during construction as part of the "long hull" group, with the bow extended into a "clipper" shape to provide room for additional anti-aircraft armament.

Nineteen more "Essex"es were ordered or scheduled, starting with ten on August 7, 1942. Only two, USS|Bon Homme Richard|CV-31|3 and USS|Oriskany|CV-34|3 were laid down as "Essex" "short hull" keels. The remainder became "Ticonderoga"-class or "long hull" ships.

USS|Lexington|CV-16|1 was originally laid down as "Cabot", but was renamed during construction after USS|Lexington|CV-2|3 was lost in the Battle of the Coral Sea in May 1942; she was commissioned on February 17, 1943. USS|Yorktown|CV-10|1, originally to be named "Bon Homme Richard", was renamed after the USS|Yorktown|CV-5|3 was lost at the Battle of Midway on June 7, 1942. USS|Wasp|CV-18|1's name was changed from "Oriskany" after the USS|Wasp|CV-7|3 was sunk in September 1942 in the South Pacific while escorting a troop convoy to Guadalcanal, and CV-12's name was changed from "Kearsarge" after USS|Hornet|CV-8|3 was lost in October 1942 in the Battle of Santa Cruz Islands.

In summary, during WWII and until its conclusion by Allied forces, the US Navy ordered 32 aircraft carriers of the "Essex"- and related "Ticonderoga"-classes, of which 26 were laid down and 24 actually commissioned.

Design

In drawing up the preliminary design for USS "Essex" (CV-9), particular attention was directed at the size of both her flight and hangar decks. Aircraft design had come a long way from the comparatively light planes used in carriers during the 1930s. Flight decks now required more takeoff space for the heavier fighters and bombers being developed. Most of the first-line carriers of the pre-war years were equipped with flush deck catapults, but owing to the speed and size of these ships very little catapulting was done — except for experimental purposes.

With the advent of war, airplane weights began to go up as armor and armament got heavier; aircrew complements also increased. By the war's end in 1945, catapult launches would become more common under these circumstances, with some carrier commanding officers reporting up to 40% of launches by catapult.

The hangar area design came in for many design conferences between the naval bureaus. Not only were the supporting structures to the flight deck required to carry the increased weight of landing and parked aircraft, but they were to have sufficient strength to support the storing of spare fuselages and parts (50% of each plane type aboard) under the flight deck and still provide adequate working space for the men using the area below.

One innovation in "Essex" was a portside deck-edge elevator in addition to two inboard elevators. Earlier, experiments with a ramp arrangement between the hangar and flight decks, up which aircraft were hauled by crane, proved too slow. The Navy's Bureau of Ships and the Chief Engineer of A.B.C. Elevator Co. designed the engine for the side elevator. Essentially, it was a standard elevator, 60 by 34 ft (18 by 10 m) in platform surface, which traveled vertically on the port side of the ship. The design was a huge success which greatly improved flight deck operations over prior designs, with their center-deck elevators.

Since there was no large hole in the flight deck when the elevator is in the 'down' position, a critical factor if the elevator were to ever become inoperable during combat operations, the development of the deck-edge elevator was a significant improvement in flight operations. Its new position made it easier to continue normal operations on deck, irrespective of the position of the elevator. The elevator also increased the effective deck space when it was in the 'up' position by providing additional parking room outside the normal contours of the flight deck, and increased the effective area on the hangar deck by the absence of elevator pits. In addition, its machinery was less complex than the two inboard elevators, requiring about 20% fewer man-hours of maintenance.

Ongoing improvements to the class were made, particularly with regards to the ventilation system, lighting systems, and the trash burner design and implementation.

These carriers had better protecting armor than their predecessors, better facilities for handling ammunition, safer and greater fueling capacity, and more effective damage control equipment.

The tactical employment of U.S. carriers changed as the war progressed. In early operations, through 1942, the doctrine was to operate singly or in pairs, joining together for the offense and separating when on the defense—the theory being that a separation of carriers under attack not only provided a protective screen for each but also dispersed the targets and divided the enemy's attack. Combat experience in those early operations did not bear out the theory, and new proposals for tactical deployment were the subject of much discussion.

As the new "Essex"- and "Independence"-class carriers became available, tactics changed. Experience taught the wisdom of combined strength. Under attack, the combined anti-aircraft fire of a task group's carriers and their screen provided a more effective umbrella of protection against marauding enemy aircraft than was possible when the carriers separated.

When two or more of these task groups supported each other, they constituted a fast carrier task force. Lessons learned from operating the carriers as a single group of six, as two groups of three, and three groups of two, provided the basis for many tactics which later characterized carrier task force operations, with the evolution of the fast carrier task force and its successful employment in future operations.

Armaments

"Sunday Punch"

The pride of the carrier, known as the "Sunday Punch", was the offensive power of 36 fighters, 36 dive bombers and 18 torpedo planes. The Grumman F6F Hellcat would be the standard fighter, the Curtiss SB2C-1 Helldiver the standard scout aircraft and dive-bomber, and the Grumman TBF Avenger was designed as a torpedo plane but often used in other attack roles. Some late "Essex"es, such as USS|Bunker Hill|CV-17|3, also included squadrons of VoughtF4U Corsairs in fighter-bomber squadrons (VBFs), the precursor to modern fighter-attack squadrons (VFAs).

Guns, radar and radios

The defensive plan was to use radio and radar in a combined effort to concentrate anti-aircraft fire.

The design boasted four twin 5 in (127 mm)/38 caliber gun turrets, seventeen quadruple 40mm anti-aircraft guns and 65 single 20mm close-in defense guns. With a range of ten miles and a rate of fire of fifteen rounds per minute, the 5-inch guns fired the deadly VT shells. The VT shells, known as proximity fuzed-shells, would detonate when they came within convert|70|ft|m of an enemy aircraft. The 5-inch guns could also aim into the water, creating waterspouts which could bring down low flying aircraft such as torpedo planes. The Bofors 40 mm guns were a significant improvement over the 1.1"/75 caliber (28mm) guns mounted in the earlier "Lexington" and "Yorktown" classes.

The "Essex" class also made use of advanced technological and communications equipment. The Mark 4 sweeping radar was installed but could not track incoming low-level intruders and was quickly replaced with the improved Mark 12. A Plan Position Indicator (PPI) display was used to keep track of ships and enabled a multi-carrier force to maintain a high-speed formation at night or in foul weather. The new navigational tool known as the Dead Reckoning Tracer was also implemented for navigation and tracking of surface ships. Identification Friend or Foe (IFF) was used to identify hostile ships and aircraft, especially at night or in adverse weather. The four-channel Very High Frequency (VHF) radio permitted channel variation in an effort to prevent enemy interception of transmissions. It also allowed for simultaneous radio contact with other ships and planes in the task force.

The "long-hull" "Essex"es

Modifications were made throughout the "Essex" building program. The number of 20mm and 40mm anti-aircraft guns was greatly increased, new and improved radars were added, the original hangar deck catapult was removed, the ventilation system was substantially revised, details of protection were altered, and hundreds of other large and small changes were executed. In fact, to the skilled observer, no two ships of the class looked exactly the same.

Beginning in March 1943, one visually very significant change was authorized for ships then in the early stages of construction. This involved reshaping the bow into a "clipper" form to provide deck space for two quadruple 40mm mounts, improving forward antiaircraft protection. Thirteen ships were completed to this design (which became known as the "Ticonderoga" class), four in 1944, in time to join their short-hull "Essex"-class sisters in the Pacific War. The rest entered commission between early 1945 and late 1946. The U.S. Navy never held any institutional difference between the long-hull and short-hull Essex ships, and postwar refits and upgrades were applied to both groups equally.

Post-war rebuilds

Due to their spacious hangars, and the 1952 British innovation of the angled flight deck, "Essex"es could easily accommodate jet aircraft. The large numbers of new ships, coupled with their larger "Midway"-class contemporaries, sustained the Navy's air power through the rest of the 1940s, the Korean War era, and beyond.

Five of the long-hulls were laid up in 1946–47, along with all of the short-hulls. Eight stayed on active duty to form, with three "Midway"s, the backbone of the post-war Navy's combat strength. Though the Truman administration's defense economies sent three of the active "Essex"es into "mothballs" in 1949, these soon came back into commission after the Korean War began. Ultimately, all thirteen had active Cold War service.

"Oriskany" was completed to an improved design in September 1950, and eight earlier ships were thoroughly rebuilt to the improved "Oriskany" 27A design under the SCB-27 program in the early 1950s.Cross, Richard F., III "Essex: More than a Ship, More than a Class" "United States Naval Institute Proceedings" September 1975 pp.58-69] Six more of the earlier ships were rebuilt to an improved 27C design as the last stage of the SBC-27 program. USS Antietam (CV-36) received an experimental 10.5 degree angled deck in 1952. An improved angled flight deck became a distinctive feature of the SCB-125 program, and was applied concurrently with the last three 27C conversions and later to all 27A and 27C ships except "Lake Champlain". "Oriskany" got a combined SCB-27 and SCB-125 refit. "Shangri-La" became the first operational United States angled deck aircraft carrier in 1955.

Korean War and subsequent Cold War needs ensured twenty-two of the twenty-four ships had extensive post-World War II service, all initially with attack air groups. By 1955, seven unconverted "Essex"es were operating under the anti-submarine warfare carrier (CVS) designation established in August 1953. As the "Forrestal"-class "supercarriers" entered the fleet, seven 27A conversions were designated CVS to replace the original unconverted ships. Six of the 27As received specialized CVS modifications, including bow-mounted SQS-23 sonar. Two 27C conversions were designated CVS in 1962 and two more in 1969. Unmodernized ships began to leave active service in the late 1950s. The updated units remained active until age and the growing number of supercarriers made them obsolete, from the late 1960s into the middle 1970s. However, one of the very first of the type, USS|Lexington|CV-16|3, served until 1991 as a training ship.

Of the six unmodernized long-hull "Essex"es, three decommissioned in the late 1950s and early 1960s and were promptly reclassified as aircraft transports (AVT), reflecting their very limited ability to safely operate modern aircraft. "Boxer", "Princeton", and "Valley Forge" were redesignated Landing Platform Helicopter (LPH) amphibious assault ships for the Marine Corps, and remained in commission with their original straight decks until about 1970. The two least-modernized units went into reserve in the mid-1960s, and the rest passed out of the active fleet between 1969 and 1976. All were scrapped, most in the 1970s, although "Shangri-La" survived until the late 1980s.

Evolution of the air wing

For a typical attack carrier configuration in 1956-57 aboard "Bennington" (CVA-20), the air wing consisted of the following one squadron each of the following: FJ3 Fury, F2H Banshee, and F9F Cougar fighters, AD-6, AD-5N, and AD-5W Skyraider attack aircraft, AJ2 Savage bombers, and F9F-8P photo reconnaissance aircraft. [http://www.uss-bennington.org/airgroups.html Air Groups - Uss Bennington ] ]

By the mid to late 1960s, the attack air wing had evolved. "Oriskany" (CVA-34) deployed with two squadrons of F-8J Crusader fighters, three squadrons of A-4E Skyhawk attack aircraft, E-1 Tracers for AEW, EKA-3B Skywarrior inflight tankers, and RF-8G photo Crusader post strike surveillance aircraft. In 1970, the three A-4 squadrons were replaced by two squadrons of A-7A Corsair IIs. [ [http://www.ussoriskany.com/id17.html History of Ship Page 3 ] ] The F-4 Phantom II was considered too heavy to operate from "Essex"es.

Tasked and fitted out as an ASW carrier, the air wing of an "Essex" such as "Bennington" in the 1960s consisted of two squadrons of S-2F Trackers and one squadron of Sikorsky SH-34 ASW helicopters (replaced in 1964 by SH-3A Sea Kings). Airborne early warning was first provided by modified EA-1Es; these were upgraded in 1965 to E-1s. A squadron of A-4Bs were also embarked to provide daylight fighter protection for the ASW aircraft. [http://www.skyhawk.org/3e/va93/va93.htm]

LPH-converted ships flew only helicopters such as the UH-34 and CH-46 Sea Knight. The LPHs were sometimes also used as aircraft ferries for all branches of the U.S. armed forces. The AV-8A arrived into Marine Corps inventory too late to see regular fixed wing operations return to these ships. It was possible to launch and recover small aircraft like the OV-10 Bronco without need of catapult or arresting wires, but this was very rarely permitted on these straight-deck ships for safety reasons and to avoid interruption of helicopter operations.

The space program

Several "Essex"-class ships played a part in the United States' human spaceflight program, as recovery ships for unmanned and manned spaceflights, between 1960 and 1973.

USS|Valley Forge|CV-45 was the recovery ship for the unmanned flight of Mercury-Redstone 1A on December 19, 1960. The first spaceflight by an American was on Mercury-Redstone 3, recovered by USS|Lake Champlain|CV-39 on May 5, 1961. "Randolph" recovered the next flight, Mercury-Redstone 4, on July 21, 1961, and she was the primary recovery ship for Mercury-Atlas 6. The next manned flight, Mercury-Atlas 7, was picked up by USS|Intrepid|CV-11 on May 24, 1962, and USS|Kearsarge|CV-33 recovered the last two Mercury spacecraft, Mercury-Atlas 8, on October 3, 1962, and Mercury-Atlas 9, on May 16, 1963. [ [http://www.hq.nasa.gov/office/pao/History/SP-4201/toc.htm "This New Ocean: A History of Project Mercury"] . NASA Special Publication-4201. Loyd S. Swenson Jr., James M. Grimwood, Charles C. Alexander, 1989.]

When the Mercury program's successor, Project Gemini, got underway, "Essex"es were again closely involved. "Lake Champlain" recovered the second unmanned flight, Gemini 2, on January 19, 1965; and "Intrepid" recovered the first manned flight, Gemini 3. "Wasp" recovered the crew of Gemini IV on June 7, and on August 29, "Lake Champlain" picked up Gemini 5 after eight days in space. In December 1965, "Wasp" made history by picking up two spacecraft in just over two days: Gemini VI-A on December 16, and Gemini 7 on December 18, after their orbital rendezvous test flight. She also recovered Gemini 9A on June 6, 1966 and the final Gemini spaceflight, Gemini 12 on November 15. [ [http://www.hq.nasa.gov/office/pao/History/SP-4203/cover.htm "On The Shoulders of Titans: A History of Project Gemini"] . NASA Special Publication-4203. Barton C. Hacker and James M. Grimwood, 1977.]

The successful use of the carriers as recovery ships continued into the Apollo program. On February 26, 1966, "Boxer" recovered the command module from AS-201, the first unmanned flight of a production Apollo Command and Service Module. AS-202, another sub-orbital test flight of the command module, was recovered in August by "Hornet" (CV-12); the command module from that flight is currently on display aboard "Hornet". "Bennington" recovered the command module of Apollo 4, the first unmanned flight of the Saturn V launch vehicle, on November 9, 1967. [http://www.hq.nasa.gov/office/pao/History/SP-4205/contents.html "Chariots for Apollo: A History of Manned Lunar Spacecraft"] . NASA Special Publication-4205. Courtney G Brooks, James M. Grimwood, Loyd S. Swenson, 1979.]

Eleven months later, "Essex" recovered the astronauts of Apollo 7, the first manned mission in the Apollo program, after eleven days in orbit. USS|Yorktown|CV-10 recovered the astronauts of Apollo 8, after their historic flight around the Moon in December 1968; and USS|Princeton|CV-37 recovered the second crew to orbit the Moon, aboard Apollo 10, in May 1969.

"Hornet" rejoined the program and recovered the astronauts from the first two moon landing missions, Apollo 11 in July 1969 and Apollo 12 in November. [ [http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1969-099A "Apollo 12"] , NASA (NSSDC ID: 1969-099A)] The first steps on Earth of returning astronauts Neil Armstrong, Edwin Aldrin, and Mike Collins, are marked on her hangar deck, as part of her Apollo program exhibit. The three subsequent missions utilized amphibious assault ships as support vessels; however, "Ticonderoga" recovered the astronauts of the last two moon missions, Apollo 16 [ [http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1972-031A "Apollo 16"] , NASA (NSSDC ID: 1972-031A)] and Apollo 17 in April and December 1972. [ [http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1972-096A "Apollo 17"] , NASA (NSSDC ID: 1972-096A)]

In the post-Apollo era, "Ticonderoga" again acted as a recovery ship for the astronauts of Skylab 2, the first manned mission to Skylab, the first U.S. orbital space station, in June 1973. [ [http://history.nasa.gov/SP-4012/vol3/table2.49.htm "SP-4012 NASA HISTORICAL DATA BOOK: VOLUME III PROGRAMS AND PROJECTS 1969-1978"] , Table 2-49, Skylab 2 Characteristics]

The ships today

Four "Essex"-class ships have been preserved, and opened to the public as museums:
*USS|Yorktown|CV-10|3, at Patriot's Point, Mount Pleasant, South Carolina
*USS|Intrepid|CV-11|3, in New York City
*USS|Hornet|CV-12|3, in Alameda, California
*USS|Lexington|CV-16|3, at Corpus Christi, Texas.

Until USS "Midway" opened at San Diego, every preserved aircraft carrier in the U.S. was an "Essex".

USS|Oriskany|CV-34|2 was sunk in 2006 to form an artificial reef off the coast of Pensacola, Florida.

The "Essex" class

USS|Oriskany|CV-34|3 was ordered and laid down as an "Essex"-class vessel, was completed in 1950 to the much modified SCB-27A design.

USS|Reprisal|CV-35|3, laid down in July 1944 at the New York Navy Yard and launched in 1945, was scrapped incomplete after tests; and USS|Iwo Jima|CV-46|3 was laid down at Newport News Shipbuilding yards in January 1945 but cancelled in August 1945 and broken up on the slipway.

Six fiscal-year 1945 ships, none of which received names, were assigned to Bethlehem Steel Company (CV-50), New York Navy Yard (CVs 51 & 52), Philadelphia Navy Yard (CV-53) and Norfolk Navy Yard (CVs 54 and 55). Their construction was cancelled in March 1945.

References

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See also

* Aircraft carrier classes:
** "Yorktown"-class
** "Midway"-class
** "Forrestal"-class
* "Ticonderoga"-class cruiser
* List of aircraft carriers of the United States Navy